U.S. patent number 8,462,586 [Application Number 12/741,842] was granted by the patent office on 2013-06-11 for direction controllable lighting unit with ultrasound.
This patent grant is currently assigned to Koninklijke Philips Electronics N.V.. The grantee listed for this patent is Lorenzo Feri, Hendricus Theodorus Gerardus Maria Pening De Vries, Tim Corneel Wilhelmus Schenk. Invention is credited to Lorenzo Feri, Hendricus Theodorus Gerardus Maria Pening De Vries, Tim Corneel Wilhelmus Schenk.
United States Patent |
8,462,586 |
Schenk , et al. |
June 11, 2013 |
Direction controllable lighting unit with ultrasound
Abstract
A direction controllable lighting unit 10 for use in a lighting
system is described. The light emission of the lighting unit 10 may
be directed into different directions, e. g. by use of a
mechanically movable element 14, 60. At least two ultrasound
transmitters 20a, 20b, or ultrasound receivers 21a, 21b are
disposed at the lighting unit 10 such that they differ in position,
or in direction or shape of the spatial intensity distribution or
spatial distribution of reception sensitivity. A mobile control
element 46 has at least one corresponding ultrasound transmitter or
receiver 50. A difference between a signal from a transmitter
received at multiple receivers, or a signal of multiple
transmitters received at a single receiver is used to determine a
relative direction of the direction controllable lighting unit 10
and the control element 46, and to control the direction of the
lighting unit 10 in dependence thereof.
Inventors: |
Schenk; Tim Corneel Wilhelmus
(Eindhoven, NL), Feri; Lorenzo (Eindhoven,
NL), Pening De Vries; Hendricus Theodorus Gerardus
Maria (Mierlo, NL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Schenk; Tim Corneel Wilhelmus
Feri; Lorenzo
Pening De Vries; Hendricus Theodorus Gerardus Maria |
Eindhoven
Eindhoven
Mierlo |
N/A
N/A
N/A |
NL
NL
NL |
|
|
Assignee: |
Koninklijke Philips Electronics
N.V. (Eindhoven, NL)
|
Family
ID: |
40535628 |
Appl.
No.: |
12/741,842 |
Filed: |
November 12, 2008 |
PCT
Filed: |
November 12, 2008 |
PCT No.: |
PCT/IB2008/054738 |
371(c)(1),(2),(4) Date: |
May 07, 2010 |
PCT
Pub. No.: |
WO2009/063411 |
PCT
Pub. Date: |
May 22, 2009 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100225245 A1 |
Sep 9, 2010 |
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Foreign Application Priority Data
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Nov 16, 2007 [EP] |
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07120834 |
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Current U.S.
Class: |
367/118 |
Current CPC
Class: |
H05B
45/20 (20200101); H05B 45/00 (20200101); G01S
11/14 (20130101); H05B 31/50 (20130101); H05B
47/155 (20200101); F21V 14/02 (20130101); G01S
3/801 (20130101) |
Current International
Class: |
G01S
3/80 (20060101) |
Field of
Search: |
;367/118 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO9514241 |
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May 1995 |
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WO |
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WO0216824 |
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Feb 2002 |
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WO |
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WO2004039631 |
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May 2004 |
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WO |
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WO2006111927 |
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Oct 2006 |
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WO |
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WO2007072314 |
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Jun 2007 |
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WO |
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WO2009003279 |
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Jan 2009 |
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WO |
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Primary Examiner: Alsomiri; Isam
Assistant Examiner: Hulka; James
Attorney, Agent or Firm: Salazar; John F. Beloborodov; Mark
L.
Claims
The invention claimed is:
1. A direction-controllable lighting unit, comprising a
mechanically movable element for directing a light emission into
different directions along a light emission output axis; at least
two ultrasound transmitter units disposed at said movable element
for moving therewith, wherein said at least two ultrasound
transmitter units are disposed at said lighting unit in such a way
that they differ in at least one of: position, direction of spatial
intensity distribution of emission, shape of spatial intensity
distribution of emission, direction of spatial distribution of
reception sensitivity, or shape of spatial distribution of
reception sensitivity and are offset from said light emission
output axis, said ultrasound transmitter units are operable to
transmit distinguishable ultrasound signals, a mobile control
element including at least one ultrasound receiver unit, and
control means to evaluate a signal received at the at least one
receiver unit, wherein a difference between signals of different
transmitter units received at the receiver unit is used to
determine a relative direction of said direction controllable
lighting unit and said control element, and to control the
direction of said controllable lighting unit dependent on said
relative direction.
2. A direction controllable lighting unit according to claim 1,
wherein said movable element for directing a light emission
comprise driving means to control a plurality of light sources
facing in different, fixed directions to direct a resulting sum
light emission, wherein said sum light emission is directed by
controlling a relative intensity of light emission from said light
sources.
3. System according to claim 1, wherein said control means are
disposed to control said controllable lighting unit such that its
direction is adjusted to point to the position of said mobile
control element.
4. System according to claim 1, wherein said control means is
disposed to evaluate said difference relating to at least one of
phase or amplitude of said signal.
5. System according to claim 4, wherein both said signals are
received at said receiver unit, wherein said control means are
disposed to analyze at least one parameter relating to a difference
between said signals, where said parameter is dependent on at least
one of phase or amplitude of said signals, and wherein said signals
are distinguishable by the use of a time, code and/or frequency
multiple access technique.
6. System according to claim 1, wherein said control means is
disposed to activate said ultrasound transmitters only in a
direction control mode of said lighting unit, where the direction
is to be adjusted, and to deactivate said ultrasound transmitters
in an operating mode, where adjusted direction is held constant for
lighting operation.
Description
FIELD OF THE INVENTION
The present invention relates to lighting units and control
thereof, and more specifically to a direction controllable lighting
unit, a controllable lighting system comprising at least one
direction controllable lighting unit and a method for controlling a
lighting system with at least one direction controllable lighting
unit.
BACKGROUND OF THE INVENTION
Direction controllable lighting units are known and used e. g. in
lighting for entertainment purposes, such as in nightclubs and
theatres. In the present context, the term "direction controllable"
will be used to refer to lighting units which have a directed light
emission, i. e. that has a specific direction as opposed to
isotropic light emission (e. g. spot lights), where the direction
of this light emission is automatically (non-manually)
controllable.
WO 2007/072314 discloses a lighting system with lighting units in
light fixtures and a remote control device. The remote control
device transmits via a transceiver therein a signal. Upon receipt
of the signal, the light fixtures transmit response signals. The
remote control may then be used to control various parameters of
the nearest light source, such as the beam direction thereof, e.g.
by control of a motor or filter device for pan and tilt operation.
Further, the remote control calculates its location or distance
relative to the light fixtures, e.g. through triangulation, signal
strength, time of flight or beam direction. The communication over
the transceiver may be radio, such as e.g. Zigbee or Bluetooth, but
could also be an RFID or ultrasound tag. The remote control may be
configured to control the directivity of the lamps towards its
location, e.g. by changing direction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a direction
controllable lighting unit which facilitates directional control,
especially automatic directional control. This object is solved by
a direction controllable lighting unit according to the claims.
The inventors have recognized that prior direction controllable
lighting units and control systems provide little information which
may suitably be used for automatic directional control. Therefore,
it is a basic idea of the invention to provide, at the lighting
unit, at least two ultrasound transmitter and/or receiver units,
which are arranged in a way such that their ultrasound emission
(transmitters) or ultrasound reception (receivers) differs. A
corresponding lighting unit may therefore transmit and/or receive
ultrasound signals which may advantageously be used for controlling
the direction of the light emission of the lighting unit in a
desired way.
The lighting unit according to the embodiments of the invention is
direction controllable, and therefore comprises means for directing
the light emission into different directions. As will become
apparent in the following detailed description, such light
directing means may be understood broadly to cover any means suited
to change the light emission direction, e. g. to change the angle
of an optical axis defined as the center of intensity of the
emitted light bundle or beam. Such means include mechanical means
(e. g. a motor for a light source fixture or of an optical element,
e. g. a rotatable lens) as well as electrical means (e. g. using
voltage sensitive optical devices). Further, in accordance with a
preferred aspect of the invention, a direction controllable
lighting unit may also comprise a plurality of light sources facing
into different, fixed directions and a corresponding driving means
for controlling these light sources to vary the relative intensity
and thereby influence the direction of the resulting summarized
light emission.
Further, according to embodiments of the invention, there are first
ultrasound means provided at the lighting unit comprising at least
two ultrasound transmitter and/or receiver units. These are
arranged at the lighting unit such that they have different spatial
reception or emission characteristics.
This means, that--in the case of transmitters--they provide
different ultrasound emissions. These different transmissions may
be achieved by arranging the transmitters in different positions,
i. e. at a distance to each other, or--in the case of a directed,
i. e. non-isotropic emission pattern--in different directions, such
that they are arranged at an angle. Also, the ultrasound emissions
may differ in shape (e. g. narrow emission/wide emission), or any
of the above mentioned differences may be combined. Thus, in the
case of transmitters, the emitted ultrasound will differ, so that
at reception positions the ultrasound signal emitted by the two
transmitters will be received differently, e. g. with regard to
amplitude and/or phase.
In the case of receiver units, these are also arranged differently
at the lighting unit. They may differ in position and/or in
direction (if they have a directed, i. e. non-isotropic reception
sensitivity). Alternatively or in addition they may have a
differently shaped spatial distribution of reception sensitivity
(e.g. broad/narrow). In the case of two ultrasound receivers there
will thus be a configuration where ultrasound transmissions from
transmitter positions will be received differently at the receiver
units, e. g. with different amplitude and/or phase.
The thus provided first ultrasound means at the lighting unit serve
to give additional information which may be used for controlling
the direction of the lighting unit. This may be used in a lighting
system which has at least one direction controllable lighting unit
as described above and a mobile control element with second
ultrasound means, complementary to the first ultrasound means of
the lighting unit (i. e. if the lighting has transmitters, the
mobile control element will have at least one receiver; if the
lighting unit has receivers, the mobile control element will have
at least one associated transmitter).
In order to control the direction of the direction controllable
lighting unit with regard to the position of the mobile control
element, an ultrasound signal is sent from a transmitter and
received by a receiver. If the lighting unit has two receivers, the
transmitter in the control element transmits an ultrasound signal
which is received by the two receiver units in the lighting unit.
Due to the different arrangement or reception characteristics of
the receivers in the lighting unit, the signal will be received
differently by the two receivers. Similarly, if the lighting unit
has two transmitters, these both emit ultrasound signals, which are
received at the control element. Due to the differences between the
transmitters' positions, directions or characteristics, the
ultrasound receiver there receives the signals from the two
transmitters differently.
Subsequently, the mentioned difference between the signals is
evaluated to determine a relative direction of the direction
controllable lighting unit in relation to the position of the
mobile control element. Then, the direction of the controllable
lighting unit may be controlled by using this information, e. g. to
point the lighting unit towards the control element's position.
In a simple example, if a lighting unit has a first ultrasound
transmitter pointing to the right, and a second ultrasound
transmitter pointing to the left, an observer identifying received
ultrasound as coming from the first transmitter can gather from
this the information that the lighting unit is pointed to his left.
In case the observer simultaneously receives ultrasound from both
transmitters, a comparison of received intensities of the signals
may yield information if the lighting unit is pointed directly
towards the observer (such that signals from both transmitters are
received at the same intensity), or if an offset remains.
Therefore, a lighting unit according to embodiments of the
invention may greatly facilitate any type of control task related
to automatically controlling the direction of the lighting
unit.
There are various preferred optional aspects of the invention. The
light source of the lighting unit may of course be any known type,
such as incandescent lamp, discharge lamp, fluorescent lamp or LED
lamp. The control element is a mobile, preferably handheld device,
which may be wire connected but is preferably wireless. The control
means may be arranged within the lighting unit, within the mobile
control element or elsewhere. They may be implemented as suitable
electronics such as a microcontroller or microprocessor executing a
corresponding program. It should be noted that the control means
need not necessarily be a single, dedicated assembly, but may be
implemented also by an assembly serving the control purposes among
other tasks, such as e. g. a main processor that executes a control
program as one of several programs serving different purposes.
Further, it is preferred that the control means are provided with
some type of connection (e. g. cable, such as direct control
connections or powerline, as well as wireless, such as radio or
infrared) both to the optical sensor and to the lighting unit. The
control means automatically controls the direction of the lighting
unit (by driving its directing means over the connection) based on
information received from the mobile control element.
According to a preferred embodiment, the first ultrasound means at
the lighting unit comprise at least two ultrasound transmitter
units, which transmit distinguishable ultrasound signals. The
signals may be distinguishable in many ways, e. g. as ultrasound
signals of different frequency. Also, the ultrasound signals may be
differently modulated, e. g. as amplitude or frequency modulation.
In this way, an identifier may be associated with each ultrasound
transmitter unit, where the identifier is different between the two
ultrasound transmitters (and in a lighting system comprising
multiple controllable lighting units as described above is
preferably unique among all ultrasound transmitters).
By providing such an identifier, the ultrasound signals emitted
from the transmitters become distinguishable by a suitable
observer, i. e. an ultrasound receiver with the ability to
recognize the identifier e. g. by analyzing the frequency or by
demodulating the received signal. Since the transmitters are
mounted to emit ultrasound with different spatial distribution, the
information about the reception of the different ultrasound signals
contains information about the direction of the direction
controllable lighting unit relative to the observer.
According to one embodiment, the controllable lighting unit
comprises a mechanically movable element for directing the light
emission. This may be a moving structure on which one or more light
sources are mounted. Alternatively it is also possible that the
movable element is an optical element, such as a lens or reflector,
which by its movement directs the light from one more lighting
units into different directions. While it is possible to arrange
the ultrasound means in a fixed position at the lighting unit,
according to a preferred embodiment they are disposed to move with
the movable element. This allows to use the above mentioned means
to not only obtain information about the relative orientation of
the position of the lighting unit and the mobile control element,
but instead information about the relative orientation of the
current lamp direction and the position of the mobile control
element, which may more easily be used for control purposes,
especially for feedback control.
In alternative embodiments, where the light emission of the
lighting unit is directed without using mechanically movable
elements, it is preferred that the first ultrasound means are
arranged at the lighting unit in fixed positions. By using the
above described processing of a difference between received
signals, it is then possible to obtain information about the
relative orientation of the position of the lighting unit and the
mobile control element, and to control the direction of the light
emission accordingly.
As an example of a direction controllable lighting unit without
mechanically moving parts, there may be provided a plurality of
light sources facing in different, fixed directions. A resulting
sum light emission may be directed by controlling a relative
intensity of light emission from the light sources. So, the light
emission may be directed e. g. in a first direction by driving a
first light source with a first level of intensity and a second
light source with a second level of intensity, and into a second
direction by driving the first light source with a third level of
intensity and the second light source with a fourth level of
intensity. If the quotient of a first and second level is different
from the quotient of the third and fourth level, the resulting sum
light emissions will point into different directions.
According to further developments, the difference evaluated relates
to phase and/or amplitude of the received signals. For example, a
phase difference and/or an amplitude quotient may be evaluated to
obtain information about the relative position or orientation. In a
particularly preferred embodiment, the first ultrasound means
comprises transmitters emitting distinguishable ultrasound signals
and the resulting ultrasound signal received at the mobile control
element is analyzed determining a parameter dependent on a phase
and/or amplitude difference between the signals. It is particularly
preferred that the signals are distinguishable by the use of
multiple access technique such as CDMA, TDMA or FDMA.
During control of the lighting unit in relation to the mobile
control element it is of course possible to use the position of the
mobile control element as a reference only, and to point the light
source into a direction dependent on that position, but not exactly
aiming at the mobile control element. However, in order to
facilitate handling of control it is preferred that the
controllable lighting unit is adjusted to point to the position of
the mobile control element. In this way, it is very easy for a user
to e. g. direct light spots to point at desired locations by
placing the mobile control element there. Multiple lighting units
comprised in a system may be controlled individually, all together
or in selected groups. As a further feature, it is possible that
the first ultrasound means will only be activated in a direction
control mode of the lighting unit, but be deactivated in subsequent
normal lighting (operating mode).
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will become apparent from the following description of
preferred embodiments, in which:
FIG. 1 shows a schematical side view of a first embodiment of a
direction controllable lamp;
FIG. 2 shows a schematical representation of an electrical
connection of elements of the lighting unit of FIG. 1;
FIG. 3 shows a lighting system comprising a direction controllable
light as shown in FIG. 1;
FIG. 4 shows in schematic form a mobile control element of the
system of FIG. 3;
FIG. 5 shows a schematical side view of a second embodiment of a
direction controllable lamp;
FIG. 6 shows a schematical representation of an electrical
connection of elements of the lighting unit of FIG. 3;
FIG. 7 shows a schematic side view of a third embodiment of a
direction controllable lamp;
FIG. 8 shows a schematic side view of a fourth embodiment of a
direction controllable lamp;
FIG. 9a, 9b show different embodiments of direction controllable
lamps;
FIG. 10 shows a further embodiment of a lighting system comprising
multiple direction controllable lamps.
DETAILED DESCRIPTION OF EMBODIMENTS
FIG. 1 shows in a side view a first embodiment of a direction
controllable lighting unit (luminary) 10. A lighting unit comprises
a mounting part 12 and a fixture 14 which is mechanically movable
relative to the mounting part 12 in a motor-driven joint 16.
The fixture 14 carries a light source 18 and ultrasound means,
which in the example of the first embodiment are ultrasound
transmitters 20a, 20b. The light source 18 emits a directed beam of
light 22 (spot light) around a central optical axis 23, the
directional distribution (solid angle) of which is achieved by a
suitable reflector (not shown).
The ultrasound transmitters 20a, 20b are arranged at the fixture 14
to transmit ultrasound signals 24a, 24b with spatial intensity
distributions with central axes 26a, 26b. The ultrasound emissions
24a, 24b of the ultrasound transmitters 20a, 20b thus differ in
spatial intensity distribution. In the shown preferred example,
they differ both in position and in emission direction, i. e. the
axes 26a, 26b are arranged at an angle .alpha.. Also, the
ultrasound emissions 24a, 24b of the ultrasound transmitters 20a,
20b differ from the direction of light emission 22 from the light
source 18, i. e. there is an angle .beta. between the axes 26a, 26b
and the central optical axis 23 of the main light sources' 18 light
emission 22.
Alternatively, it would also be possible that the ultrasound
transmitters 20a, 20b are arranged at a distance as shown, but emit
ultrasound into parallel directions. This is shown in FIG. 7. As a
further alternative, shown in FIG. 8, the emissions could be in the
same direction, even with a common axis 26, if they have different
shape, e. g. a first, broad emission 24a and a second, narrow
emission 24b.
It should be noted that the controllable lighting unit 10 shown
here is only represented schematically. The motor-driven joint 16
is not shown in detail. Different kinds of motor-driven movable
mounting of lighting units are known per se to the skilled person.
The type of the light source 18 may be chosen quite differently
among available light sources, such as incandescent lamps, arc
discharge lamps, fluorescent lamps and high power LEDs, as long as
they are suited for lighting purposes, i. e. provide visible light
at an intensity high enough to illuminate a certain area, e. g.
parts of a room. Also, there may be multiple light sources provided
as main light source(s), such as e. g. an array of LEDs, multiple
incandescent lamps or even combinations of different types of light
sources.
It should be noted that in the example of FIG. 1, the movement of
the lighting unit is shown only as rotation around one axis, namely
the axis of the joint 16. Thus, movement may be described as a
plane angle .gamma., which may be defined between the central
optical axis 23 of the light source 18 and the horizontal
direction. While it is possible to provide a lighting unit 10 the
direction of which is only controllable in one dimension as shown,
it should be clear to the skilled person that the underlying
concept of course extends to multi-dimensional movement, such that
directions may then be defined by solid angles rather than plane
angles. This of course also applies to the arrangement of
ultrasound transmitters 20a, 20b relative to each other (angle
between axes 26a, 26b) as well as relative to the optical axis 23
of the light source 18.
FIG. 2 shows a simplified schematical diagram of the fixture 14
with the ultrasound transmitters 20a, 20b and the light source 18.
An electrical connection 28 is provided to supply electrical
energy. In order to provide distinguishable ultrasound signals, the
transmitters are operated at the same basic ultrasound frequency,
but with different modulation. To achieve this, modulation driver
circuits 30a, 30b are provided to drive the transmitters 20a, 20b
according to a modulation scheme.
The modulation may be a simple on/off control of the transmitters
20a, 20b. However, it is especially preferred that the emitted
ultrasound signals are modulated using a spread spectrum technique
known as "code-division multiple access" (CDMA). The individual
codes, which may here be designated "A" or "B" respectively, are
orthogonal to each other, i. e. a value of an autocorrelation of a
code is significantly higher than a value of a cross correlation of
two different codes. Thus, a demodulator may use the predetermined
codes to discriminate between simultaneous transmissions of
modulated ultrasound signals by different sources 20a, 20b. Also,
in a preferred embodiment a synchronous CDMA codes, such as
pseudo-noise (PN) sequences can be applied, since they do not
require a common clock for the different transmitters. In an even
further solution the signals for the different transmitters can be
distinguished in the time or frequency domain, using "time-division
multiple access" (TDMA) or "frequency-division multiple access"
(FDMA), respectively.
The driver units 30a, 30b thus modulate the ultrasound emission
24a, 24b of the transmitters 20a, 20b such that they contain
different identification codes. For example, the signal 24a emitted
by the first transmitter 20a may contain a code "A", whereas the
signal 24b emitted from the second transmitter 20b contains a code
"B".
Use of the controllable lighting unit 10 with the described
modulated transmitters 20a, 20b pointing in different directions
26a, 26b will be explained with regard to FIG. 3, which shows a
lighting system 40, e. g. in in a room, with multiple light
sources. A conventional, fixed light source 42 is provided, e. g.
mounted at the ceiling of a room. Further, the controllable
lighting unit 10 is also mounted there. The lighting unit 10 is
connected to a control unit 44 such that the control unit 44 may
control the direction of the light emission, which in the example
as explained above may be described by the angle .gamma..
A mobile control element 46 is arranged within the area that may be
illuminated by the lighting unit 10. The control element 46 is
connected to the control unit 44.
FIG. 4 shows the control element 46 in schematic form. It comprises
an ultrasound receiver (microphone) 50 which receives an ultrasound
signal and produces a corresponding electrical signal. The
electrical signal is demodulated by a demodulation unit 52 to
extract those portions of the received signal that are modulated
according to codes "A" and "B". The modulation unit 52 delivers the
correspondingly demodulated portions of the signal to measuring
devices 54a, 54b which deliver a value representative of the phase
and/or amplitude of the received signal portion modulated with
codes "A", and "B", respectively. The values are then passed to an
interface unit 56 and delivered to the control unit 44.
Thus, while the mobile control element 46 in the lighting system 40
of FIG. 3 might receive ultrasound signal contributions from other
sources besides transmitters 20a, 20b, the signal passed on to
control unit 44 only comprises information about the received
intensities of the modulated signals 24a, 24b from the controllable
lighting unit 10.
This allows control unit 44 to control the direction of lighting
unit 10. For example, it may be desired to direct lighting unit 10
to point to the location of the control element 46. With the
position of lighting unit 10 as indicated in FIG. 3, it is clear
that the lighting unit is directed too far to the right. This leads
to a relatively strong incident signal 24a from the first
ultrasound transmitter 20a, which is modulated according to code
"A", whereas no or only a small signal modulated with code "B" is
received from the second ultrasound transmitter 20b. From this
information, transmitted to the control unit 44, the unit 44 may
determine that the lighting unit 10 is directed too far to the
right. A quotient of the received intensities will even yield a
certain measure of the angular value of misalignment.
The control unit 44 thus sends corresponding control commands to
the motor joint 16 to move lighting unit 10 a certain distance to
the left. Then, a further measurement of amplitudes of the
ultrasound signals is effected by the control element 46, such that
the control unit 44 receives information indicating if the
alignment is now correct (same intensity of ultrasound emissions
24a, 24b received), or if a further correction to the left
(emission 24a stronger) or even to the right (emission 24b
stronger) is necessary. The control unit 44 may thus employ a
closed-loop control to direct lighting unit 10 exactly such that
its optical axis 23 is directed to the place of the control element
46.
Alternatively, control element 46 could evaluate the phase
difference between the signals from sources 20a and 20b. When the
phase difference is minimized, the lamp is pointing at the control
element.
FIG. 5 shows an alternative embodiment of a lighting unit 11. The
lighting unit 11 largely corresponds to the lighting unit 10
described in connection with FIG. 1. Like parts are referenced by
like numerals. In the following, only differing parts will be
further explained.
Instead of two ultrasound transmitters as in the first embodiment,
the lighting unit 11 according to the second embodiment comprises
two ultrasound receivers (microphones) 21a, 21b. The receivers
shown in the present example have directed reception
characteristics, so that their reception sensitivity is not
isotropic, but differs dependent on direction. These directional
characteristics are shown symbolically in FIG. 5 as reception
regions 23a, 23b. It is of course understood by the skilled person
that actual directional reception characteristics of a microphone
are defined by three-dimensional shape. For each reception region
23a, 23b, there may be a central axis 26a, 26b defined.
In the example of FIG. 5, the ultrasound receivers 21a, 21b are
arranged at a distance to each other on the mechanically moving
fixture 14. Further, there are arranged in different directions, i.
e. such that their central axes 26a, 26b are arranged at an
angle.
Resulting from this, the way ultrasound signals from transmitter
positions are received at both receivers 21a, 21b will generally
differ (in the shown example, only ultrasound signals emitted from
positions on the central axis 23 will be received equally by both
receivers). This is used to effect automatic control of the
lighting unit 11 in a lighting system, where a mobile control unit
(not shown) has a single ultrasound emitter.
The ultrasound emitter emits an ultrasound signal which may be
constant or modulated, e. g. with an identifier or code.
As in the first example of a lighting system, the mobile control
element with, in this case, an ultrasound transmitter, is placed
within the area which may be illuminated by lighting unit 11. The
ultrasound signal from the transmitter is received by both
receivers 21a, 21b. Within the lighting unit 11, as shown in FIG.
6, there is arranged a processing circuit 27 connected to the
electrical connection 28. Processing circuit 27 processes the
signals received at the receivers 21a, 21b by identifying--among
possible noise--in both signals the contribution from the
transmitter and by comparing these two signals.
If the emitted ultrasound signal is modulated with a code, it can
be better distinguished from other ultrasound signals or noise
influences. In this case, there may be demodulation effected in the
processing circuit 27 as indicated in FIG. 6 by correlating the
received signals with the prior known code. This will suppress
other signal contributions and yield signals for the later
comparison that only contain the relevant information. Of course,
in the case of a non-modulated ultrasound signal, the correlator
units in processing circuit 27 may be omitted.
In a first variant, the comparison relates to the amplitude of the
signals. An amplitude quotient is determined and passed on to a
controlling unit 29. The controlling unit 29 controls the direction
control means--in the present example the motor driven joint
16--according to the value of this quotient. For example, if the
quotient of the amplitude of the signal received in receiver 21a
divided by the amplitude of the signal received in receiver 21b is
above 1, then the lighting unit is moved in the direction of
receiver 21b (i. e. in the example of FIG. 5 to the right),
otherwise in the opposite direction. This is repeated until the
quotient reaches a value of 1, so that now the lighting unit 11
points directly at the mobile control element (such that the
ultrasound transmitter there is located on central axis 23).
In a further variant, the receipt signals are compared with regard
to phase. A phase difference is determined and passed on to
controlling unit 29. Controlling unit 29 controls the direction
control means 16 to minimize the phase difference, also leading to
a configuration where the lighting unit 11 will be pointed at the
mobile control element.
As in the first embodiment, also the lighting system according to
the second embodiment may use further external control effected
over a suitable connection, e. g. powerline communication over
electrical supply 28.
While in the forgoing embodiments lighting units where shown to be
direction adjustable by a mechanically moveable fixture 14, it is
also possible to achieve directional control of the light emission
of a lighting unit in different ways, as will next be explained
with reference to FIG. 9a, 9b. It should be noted that while the
examples described and shown in the preceding Figs. may refer to a
motor joint as means for controlling direction, this is given as an
example only and should not be construed as limiting. Instead, it
is possible to exchange the shown and described lighting units with
a motor joint by alternative lighting units as will next be
described.
As shown in FIG. 9a, direction of the light emission into different
directions (designated here -2 . . . 2) may be achieved by
mechanical movement, e. g. rotation, of an optical device 60
positioned in the beam path of a light source 18 (in this case
shown to be an LED, but the light source 18 could, of course, be of
any other type). The optical device shown may be e. g. a lens, or a
diffusor, and may be moved e. g. by a motor. Alternatively, the
optical device may be a reflector. The position of the optical
device controls the direction of the light emission. As in the
above described case of mechanical movement of the fixture 14, not
only rotation in the shown plane, but also around a perpendicular
axis is possible.
In a further embodiment shown in FIG. 9b, a lighting unit 11
comprises a plurality of individually controllable light sources 64
mounted on a common body 66 such that they emit a directed light
emission into different directions. The whole range of possible
light emissions from lighting unit 11 is designated in FIG. 9b as
beam pattern 68, and is made up by bordering light emissions from
the individual light sources 64. Alternatively, the light emissions
may also be overlapping.
A control circuit 70 is provided which receives input commands for
a desired intensity and direction of the light emission from
lighting unit 11 and drives the individual light sources 64 to
achieve, as a resulting sum output, the desired emission. This is
achieved without mechanical movement of any part of lighting unit
11. For example, if emission only in direction 0 is desired, the
control device 70 may control the light sources 64 such that they
are all switched off, except for the central light source pointing
in the "0" direction. Similarly, if a beam direction of "-2" is
desired, only the light source 64 to the left would be switched on.
In case of desired light emission in between two directions at
which light sources 64 are provided, e. g. for a light direction of
"-1.5", this may be achieved by operating certain light sources 64
in a partially dimmed state, e. g. by operating the two left most
LEDs at 50% light contribution.
Thus, lighting unit 11 may achieve a directed illumination within a
substantial range 68 without any mechanically moving parts.
The shown light sources 64 here are preferable LEDs, as shown in
the figure, but may alternatively of course be other, preferable
dimmable types of light sources.
Also mounted at the lighting unit 11 are ultrasound means, in the
shown example a plurality of (here shown: 4) ultrasound receivers
21, also mounted in mechanically fixed way. As described above, the
ultrasound signals received by ultrasound receivers 21 may be
processed to determine the relative orientation towards an
ultrasound transmitter, the signal of which is received in each of
the ultrasound receivers 21. For example, know array processing
techniques utilizing phase differences in the signal received at
the individual receivers 21 may be used, such as described in the
article "Two Decades of Array Signal Processing Research" by Hamid
Krim and Mats Viberg in IEEE Signal Processing Magazine, July 1996,
pp 67-94.
After thus the relative orientation towards a mobile control
element with an ultrasound transmitter is determined, the control
device 70 may accordingly control the light sources 64 of the
lighting unit 11 to point into the determined direction.
FIG. 10 shows a further lighting system 80 to illustrate in an
example how multiple direction controllable lighting units 10, 10'
may be controlled. It should be noted that the shown type of
direction controllable lighting units 10, 10', which are
controllable by motor joints, have a halogen lamp as main light
source, and have two transmitters as first ultrasound means are
given as an example only, and of course could be replaced by any of
the further described lighting units, methods of controlling
direction and types of light sources.
In the case of multiple direction controllable lighting units as
shown in the lighting system 80 of FIG. 10, the embedded codes in
the ultrasound emission of the sources are unique. Thus, e. g. the
ultrasound transmitter to the left of the first direction
controllable lighting unit 10 may be distinguished by its embedded
code not only from the other transmitter of the same lighting unit,
but also from all other ultrasound transmitters of other lighting
units.
The user, who wants to control the lighting system 80, proceeds as
follows:
First, the directional lighting unit of which the direction is to
be controlled first is identified. This could be done e. g. by
holding the mobile control element 46 close to the ultrasound
emitting part of the lighting unit, so that the control element 46
now identifies the codes emitted to identify the lighting unit.
Another method could be by use of a user interface device which
identifies the controllable lighting devices. A selected lighting
unit may start flashing, so that the user can identify the
presently selected lighting unit.
Another method would be to put the control device in the light beam
of the spot. Based on the difference in amplitude/phase of pairs of
codes/identifiers/signals, the device can select the lamp to be
controlled, e.g. the lamp where the signals from the two sources
have the lowest phase/amplitude difference.
After the selection is effected, the control element 46 is placed
at a location where the emitted light from the directional light
source is supposed to be targeted. The user then initiates
automatic control, so that control unit 44 automatically adjusts
the selected lighting unit 10 to point to this location.
Control is effected as described above by measuring the
contribution of the individually coded ultrasound emissions in the
signal received at the control element 46 and communicating the
demodulated information to the control unit 44. Here a desired
direction of the lighting unit 10 is calculated by a closed-loop
control algorithm based on the current measurement, or together
with a set of previous measurements. This direction is communicated
to the direction controllable lighting unit 10, so that the
lighting unit 10 changes its emission direction based on the
communicated control data (which change could be effected, e. g.,
according to one of the embodiments described above).
The measurement and adjustment steps described above are repeated
until a satisfactory result is achieved.
Within control unit 44, control is thus effected according to a
control algorithm which yields in each step the new direction of
the lighting unit 10. An example of a control algorithm could be to
try a discrete set of possible directions and chose the one with
the highest score according to the evaluation criteria. Other
methods could be based on adaptive filtering (LMS, RLS algorithms)
or other optimization techniques known per se to the skilled
person.
After direction of the first lighting unit 10 has thus been
adjusted, the user may now proceed to adjust direction of a second
controllable lighting unit 10'. This lighting unit may be directed
to the same location, or the control element 46 may be moved to
direct the second lighting unit 10' to a different location.
Alternatively, it is also possible to simultaneously control both
(or in the case of further available lighting units: all, or at
least a subset) of the direction controllable lighting units in the
lighting system 80, such that they are all directed to the location
of the optical sensor 46.
While in the above described examples directional control is only
effected in a 2D plane, the concept of course also applies to 3
dimensions.
The invention has been illustrated and described in detail in the
drawings and foregoing description. Such illustration and
description are to be considered illustrative or exemplary and not
restrictive; the invention is not limited to the disclosed
embodiments.
There are a plurality of further features possible, such as
Alignment of Spots with Offset to the Mobile Control Element
In the above examples it was shown how the lighting units could be
controlled to point directly to the control element 46. It should
be noted that it is of course also possible to automatically obtain
a lighting direction with a predetermined--fixed or variably
chosen--offset angle. E. g. the operator could choose to adjust a
spot such that it should point a predetermined angle, say
10.degree., above the position of the control element 46.
Times at which Ultrasound Signals are Transmitted
In the foregoing text, the lighting units and ultrasound
transmitters have been described with relation to their special
feature of emitting or receiving ultrasound signals to facilitate
control. Of course, it is still the main purpose of the lighting
units to provide the desired illumination for lighting. Thus, after
control has successfully been effected, the transmitters described
above may continue to emit modulated ultrasound signals, will
preferably be in an operating mode, where the ultrasound means are
disabled until reactivated by entering a new direction control
mode.
In fact, in a system with a plurality of lighting units, the
ultrasound transmitters of each lighting unit may be operated in a
way such that they emit ultrasound signals only if their lighting
unit is specifically selected for control. Thus, an operator could
select a limited number, or even only one lighting unit for
control. The control unit would then assign codes to the
transmitters of the selected lighting unit(s). This would greatly
facilitate handling of codes, because for effective control the
codes need to be unique. If codes are consequently only used when
specifically needed, a limited number of codes may suffice. It is
even possible that in each of a plurality of lighting units the
transmitters have the same code, if it is ensured that they are not
operated (controlled) simultaneously.
Additional Control of Intensity and Color
By the techniques of this invention, it may also be possible to
control, in addition to the direction of lighting units, intensity
and/or color of the light emission. This could be done manually at
a user interface, e. g. located at the control element 46, or by an
automatic control effected through control unit 44. For example,
the intensity is increased as a function of the orientation of the
lighting unit to achieve a constant light intensity at the target
location.
In the claims, the word "comprising" does not exclude other
elements, and the indefinite article "a" or "an" does not exclude a
plurality. The mere fact that certain measures are recited in
mutually different dependent claims does not indicate that a
combination of these measures cannot be used to advantage. Any
reference signs in the claims should not be construed as limiting
the scope.
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